How to counter Ezreal
Let us take a look on how to beat Ezreal. We will look at champions who are strong against Ezreal and who are weak against Ezreal. Use win rate, gold difference and creep score difference at minute 10 to find the best 
Adc champion who counters Ezreal. You can already win in champion select with the right counters for Ezreal. If you want to know how to counter Ezreal then you need to take into account the best picks vs Ezreal and the worst picks vs Ezreal. This Ezreal counter data is based on matches played by Pros on patch 13.24 and previous ones. It is important to see whether Pros counter picked Ezreal or whether they played as Ezreal.
Champions used by Pros to counter pick Ezreal
Looking at the matches from Pros (see table Pros counter picked Ezreal) we can see that they picked 
Kai'Sa most often to counter pick Ezreal. The matchup Kai'Sa vs Ezreal occured 239 times. Ezreal has 152 wins and 87 losses in this matchup. Learn how to counter pick Kai'Sa to get another perspective on the data.
Lane outcome for Ezreal
When looking at Ezreal counters you will notice that win rates alone are not conclusional. Therefore we provide an overview (see table Lane Outcome) where you can see the lane outcome of Pros who played Ezreal. The lane outcome of Ezreal consists of three outcomes: Win, Loss or Draw. Let's take a look of Ezreal lane and match outcome for specific matchups. Considering the lane outcome and the match outcome of a specific matchup, might enable you to find the right counter for Ezreal.
Conclusion
Analyze the available data and learn how to beat Ezreal. To master Ezreal take also a look on Ezreal builds and runes for Ezreal. Good luck, Summoner!